Summary On 15August2004 at 1525 eastern daylight time, while exiting Iroquois Lock in the St. Lawrence Seaway, the bulk carrier Federal Maas struck Bridge12 at the lower end of the lock. The vessel sustained damage to its port bridge wing. Damage to Bridge12, which was not fully raised, was minimal and the lock was closed to traffic for approximately four hours. Ce rapport est galement disponible en franais. Other Factual Information Particulars of the Vessel History of the Voyage On 11August2004, the Federal Maasdeparted Burns Harbour, Chicago, United States, bound for Montral, Quebec, en route to Algeria, with 19798tonnes of corn. The vessel had an uneventful voyage downbound through the Great Lakes/St. Lawrence Seaway, arriving at Iroquois Lock at 1500 eastern daylight time2 on August15. As the Federal Maas approached Iroquois Lock, the head structures operator (HSO) and two canal structures operators (CSOs) went to the control kiosk at the upper (west) end of the lock (see Figure2). One of the CSOs opened the upper gates, raised the arrester wire boom, activated the green navigation light, and waited as the vessel proceeded into the lock. In order to ensure that the vessel could be tied up quickly in the event of propulsion or steering equipment failure, both CSOs walked along the lock wall with the vessel. The HSO accompanied CSO1 to the forward end of the vessel and assisted in securing the vessel's No.2 wire to a bit and spot the vessel into position. CSO1 then returned to the stern of the vessel to help with the tie up, before proceeding to the upper control kiosk. Photo 1. Federal Maas (by permission of Chris Franckowiak) The HSO proceeded to the lower control kiosk and, using the computer control station within, initiated the opening of Bridge12.3 Before the bridge reached its full open position, the upper approach lights were switched from green to red by CSO1 from the upper control kiosk using the lock computer control system. Shortly afterward, CSO1 informed the HSO that the upper end of the lock was ready to close, meaning that the green approach light had been switched to red. At about this time, the pilot on board the vessel requested that the HSO read the forward draught marks. The HSO proceeded out of the lower control kiosk. The bells on Bridge12 had stopped, indicating that the bridge was no longer in motion. CSO2, stationed at the upper control kiosk, then opened the lower gates and arrester boom, and the vessel was cast off, with the HSO releasing the No.2 wire at the bow. The vessel exited the lock proceeding at 1.5knots along the lower approach wall. Both the pilot and master were on the starboard side of the vessel's bridge; as such, Bridge12 was not clearly in view. As the vessel's accommodation structure passed Bridge12, the port bridge wing struck the centre of the span of Bridge12. The vessel was secured along the approach wall, and navigation through the lock was suspended for four hours while the damage to Bridge12 was assessed and temporary repairs were made to the vessel. Figure 1. Location of occurrence Damage to the Vessel and Bridge12 Damage to the vessel was confined to the port extendable section of the bridge wing and aft bridge wing bulwark. Damage to Bridge12 was minor, and was limited to a light fixture and associated wiring at mid span. Environmental Conditions Weather was clear at the time of the occurrence, with calm winds and visibility estimated at 10miles. Lock Control System Until 2001, the lock was operated from a control tower located at the lower end of the lock. At that time, a new control system was installed that comprised three computer control stations, one at each end of the lock, and a centralized station in a building midway along the lock. Figure 2. Layout of lock control stations Closed-circuit television (CCTV) cameras were installed to allow lock operators to view all equipment. Following an accident in 2003 at Lock No.3 in the Welland Canal, during which a ship arrester was lowered onto the Federal Saguenay,4 programming changes were made to the control systems at Seaway locks including Iroquois Lock. The changes made by the St. Lawrence Seaway Management Corporation (SLSMC) were as follows: When the end fully open signal is obtained, a white message end open and locked is to be displayed on the screen. When ready to operate the equipment at this end of the lock, the operator must click on unlock upper/lower end and answer Yes or No when prompted. The operator has 30 seconds to initiate the desired operation or the end will revert to locked status. After the lock is full, the gates and bridge will open. When all movement is complete, the upper end locked message appears and the upper end is then locked. At this time, the following equipment cannot be moved: upper and lower gates, upper and lower ship arresters, and bridges. The changes were not fully tested or simulated before the control system was put in use at the lock stations. Following the implementation of these modifications, the staff noted that, when the lock was opened and the message end opened and locked was displayed, equipment at both ends was locked out. The system was again modified such that one end was able to operate should the opposite end be locked out. Following this modification, another problem was noted by the staff at Iroquois Lock. In order to operate the upper end, the red light must be on. However, when the upper navigation lights are switched from green to red while the bridge is in motion, the bridge immediately stops, regardless of its position. This deficiency was noted by SLSMC staff and, on 05August2004, all operating shifts were informed verbally and a warning note was posted on the computer control stations (see Photo3); however, no formal information concerning the problem or modified procedures was passed on to the affected operating staff. Photo 3. Warning note concerning problem of bridge opening Before the computer control modifications in 2004, a bell would sound until Bridge12 was in its fully raised position. Subsequent to the modifications, however, the bell stops ringing when the bridge stops moving, regardless of its position. As the bridge opens, the mimic display at the control stations shows a bridge animation that diminishes in size relative to the angle of bridge opening. The display is such that the animation is not readily discernable during the final 10degrees of bridge opening; however, the percentage of bridge opening is indicated at all times, throughout its range of motion. There are no interlocks to prevent the gates or arrester boom from opening should the bridge not be fully raised. Lock Staffing Iroquois Lock is crewed by three Seaway employees: an HSO and two CSOs. In this instance, in addition to overseeing all lock operations, the HSO was also tasked to do the following: guide the vessel into position; raise the bridge; read and report the vessel's draught to the pilot; and let go the vessel's forward mooring wires. To complete these tasks, the HSO must be away from the central control room. At times, the locking duties are rotated among the lock staff to ensure that the required skills are maintained by all lock personnel. Either an HSO or a CSO must be in an operation station whenever equipment is in motion; however, procedure dictates that the bridge may not be operated from the upper control kiosk.